1. Field of the Invention
The present invention relates to an air cleaner that filters air flowing in an air intake system of an internal combustion engine and a method for manufacturing the same.
2. Description of the Related Art
In an internal combustion engine, evaporated fuel sometimes flows from the engine side into an air cleaner. In the conventional air cleaner, in order to adsorb the vaporized fuel, an adsorbent has been provided in the air cleaner in addition to a filter element. This adsorbent is preferably fixed in the air cleaner to prevent the adsorbent from being removed by the user.
As one example of such a technique, an air cleaner disclosed in Japanese Patent Laid-Open No. 2002-266713 is available. The air cleaner disclosed in this publication has a filter element provided so as to partition the interior of a housing into the clean side and the dust side. A plate-shaped adsorption element provided with an adsorbent is provided in parallel with the filter element. Also, on the inner surface of the housing, an inner flange projecting toward the center side so as to be parallel with the filter element is formed throughout the entire periphery. On one surface side of the inner flange, welding pins are formed. On the other hand, the adsorption element has a frame at the peripheral edge thereof. In this frame, insertion holes are formed at positions corresponding to the welding pins formed on the inner flange.
The adsorption element is attached to the housing by inserting the welding pins into the insertion holes formed in the frame of the adsorption element, collapsing the tip ends of the welding pins projecting from the surface of the frame by heating, and staking the frame by the welding pins.
However, in the technique disclosed in the aforementioned publication, it is necessary to provide a step of fixing the adsorption element. Moreover, since this step involves work in the housing, the step takes much time and effort.
In addition, in the attaching step, the adsorption element is adversely affected by heat for heating the pins, and also melt residues melting out from the tip ends of the pins at the time of heating may be generated.